Immediately after birth, there was a deep dark-red, indistinctly demarcated tumor on the right flank of the body close to the buttocks. From the beginning hemorrhages into the surrounding area were present, visible as hematomas of varying color intensity. Laboratory findings showed massive thrombocytopenia, fibrinogen not measurably low. Constellation of a Kasabach-Merritt phenomenon.
Due to the coagulation failure in the context of the Kasabach-Merritt phenomenon, new and circumscribed hemorrhages developed spontaneously during the first days of life, visible here from different-colored hematomas and small petechial skin hemorrhages.
In coronal plane T1-weighted, fat-suppressed MRI after contrast administration, the tumor accumulates contrast strongly. The combination of the clinical picture with vascular, reddish-blue tumor immediately after birth, Kasabach-Merritt phenomenon and typical imaging suggests that the diagnosis of kaposiform hemangioendothelioma is very likely.
In view of massive coagulopathy prohibiting open surgery in this location and lack of improvement with drug therapy and replacement of platelets and coagulants alone, the decision was made to embolize the hypervascularized tumor. Digital subtraction angiography (DSA) shows the highly vascularized tumor supplied mainly from the right superior gluteal artery.
These very cranial parts are now also catheterized super-selectively with the microcatheter and embolized with particles. For better navigation of the microcatheter, the vessels from a previous injection are electronically overlaid by the computer (so-called “overlay display”, white in the image).
In the final control angiography with long series after injection into the right common iliac artery, the tumor is completely devascularized. The unaffected, physiological arterial branches of the surrounding tissue are all preserved. Thus, the tumor is completely eliminated from the circulation. Activation of coagulation and consumption of platelets in the tumor has stopped.
The clinical course was very encouraging. The volume of the tumor had already decreased immediately after embolization. Platelet levels rose rapidly, as did fibrinogen and coagulation factors. The Kasabach-Merritt phenomenon was suspended. This image 17 days after embolization shows the clinical success.
The typical clinical picture of a newborn with a reddish-bluish tumor immediately after birth, massive coagulopathy with spontaneous hemorrhage and marked thrombocytopenia is clearly indicative of a kaposiform hemangioendothelioma with Kasabach-Merritt phenomenon. In this case, mere substitution of platelets and coagulation factors is usually insufficient. Super-selective embolization while preserving the healthy arteries prevents intratumoral activation of coagulation and trapping of platelets across the massively perfused tumor. This was also very successful in this infant. Currently, the patient is on sirolimus and is developing very well without recurrence.
All images © Wohlgemuth